This invention relates to a flat, multi-element writing instrument, particularly one in which the elements are manually actuated by members located on one face of the instrument.
Some writing instruments incorporate multiple writing elements and include mechanisms for selectively actuating these elements to extend them into a writing position. Some instruments also are relatively flat, providing increased comfort to the user among other advantages. Excellent examples of such a writing instrument are presented in U.S. Pat. Nos. 3,871,775 and 3,912,401, granted to the present inventor. As exemplified by the devices described in these patents, flat writing instruments incorporating multiple writing elements provide actuating members on the sides of the pen. When so positioned, these projections can engage the user's hand during use of the instrument, thereby constituting a source of irritation and, occasionally, causing the writing element to be inadvertently released and retracted while still in use. Moreover, such multi-element writing instruments can become jammed when both writing elements are attempted to be extended simultaneously from the instrument. Since such writing instruments are complex to operate, and since few users are disposed to read instructions, jamming presents a significant problem.
An object of the present invention is to provide a flat, multi-element writing instrument in which the writing elements are actuated by projections located on the face of the instrument. Also, another object of the invention is to provide an instrument incorporating means preventing even the partial extension of one writing element while the other writing element is in an extended position, thereby preventing the elements from becoming jammed in the instrument. A further object of the invention is to provide an instrument in which an extended writing element automatically is retracted upon lifting the clip, such as when attaching the instrument to the clothing of the user. Another object is to provide a writing instrument that is simple to operate, one which even an inexperienced user can operate correctly without jamming the mechanism. Still another object is to provide a writing instrument that includes large areas for advertising or designs, areas that are exposed during use and during pocket storage of the instrument.